linux/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c, branch v6.14

drm/amdgpu: drop volatile from ring buffer

2024-10-28T20:32:03Z

Volatile only prevents the compiler from re-ordering reads and writes. Since we always only modify the ring buffer from one CPU thread and have an explicit barrier before signaling the HW this should have no effect at all and just prevents compiler optimisations. While at it drop the local variables as well. Signed-off-by: Christian König Reviewed-by: Sunil Khatri Signed-off-by: Alex Deucher

drm/amdgpu: optimize insert_nop using multi dwords

2024-10-15T15:16:40Z

Optimize the ring_insert_nop fn for n dwords in one step rather then call to amdgpu_ring_write for each nop packet. This avoid function call for each nop packet and also wptr is updated once only. Signed-off-by: Sunil Khatri Suggested-by: Christian König Reviewed-by: Christian König Signed-off-by: Alex Deucher

drm/amdgpu: move error log from ring write to commit

2024-10-08T13:46:15Z

Move the error message from ring write as an optimization to avoid printing that message on every write instead print once during commit if it exceeds write the allocated size i.e ring->count_dw. Also we do not want to log the error message in between a ring write and complete the write as its mostly not harmful as it will overwrite stale data only as GPU read from ring is faster than CPU write to ring. This reduces the size of amdgpu.ko module by around 600 Kb as write is very often used function and hence the print. Signed-off-by: Sunil Khatri Suggested-by: Christian König Reviewed-by: Christian König Signed-off-by: Alex Deucher

drm/amdgpu/mes: fix mes ring buffer overflow

2024-08-13T13:57:52Z

wait memory room until enough before writing mes packets to avoid ring buffer overflow. v2: squash in sched_hw_submission fix Fixes: de3246254156 ("drm/amdgpu: cleanup MES11 command submission") Fixes: fffe347e1478 ("drm/amdgpu: cleanup MES12 command submission") Signed-off-by: Jack Xiao Acked-by: Alex Deucher Signed-off-by: Alex Deucher

drm/amdpgu: Micro-optimise amdgpu_ring_commit

2024-08-06T15:10:40Z

For some value of optimisation we can replace the division with an bitwise and. And it even shrinks the code. Before: 6c9: 53 push %rbx 6ca: 4c 8b 47 08 mov 0x8(%rdi),%r8 6ce: 31 d2 xor %edx,%edx 6d0: 48 89 fb mov %rdi,%rbx 6d3: 8b 87 c8 05 00 00 mov 0x5c8(%rdi),%eax 6d9: 41 8b 48 04 mov 0x4(%r8),%ecx 6dd: f7 d0 not %eax 6df: 21 c8 and %ecx,%eax 6e1: 83 c1 01 add $0x1,%ecx 6e4: 83 c0 01 add $0x1,%eax 6e7: f7 f1 div %ecx 6e9: 89 d6 mov %edx,%esi 6eb: 41 ff 90 88 00 00 00 call *0x88(%r8) After: 6c9: 53 push %rbx 6ca: 48 8b 57 08 mov 0x8(%rdi),%rdx 6ce: 48 89 fb mov %rdi,%rbx 6d1: 8b 87 c8 05 00 00 mov 0x5c8(%rdi),%eax 6d7: 8b 72 04 mov 0x4(%rdx),%esi 6da: f7 d0 not %eax 6dc: 21 f0 and %esi,%eax 6de: 83 c0 01 add $0x1,%eax 6e1: 21 c6 and %eax,%esi 6e3: ff 92 88 00 00 00 call *0x88(%rdx) Reviewed-by: Christian König Reviewed-by: Sunil Khatri Signed-off-by: Tvrtko Ursulin Signed-off-by: Alex Deucher

drm/amdgpu: do not call insert_nop fn for zero count

2024-08-06T14:43:28Z

Do not make a function call for zero size NOP as it does not add anything in the ring and is unnecessary function call. Reviewed-by: Christian König Signed-off-by: Sunil Khatri Signed-off-by: Alex Deucher

drm/amdgpu: Fix out-of-bounds write warning

2024-05-08T19:17:05Z

Check the ring type value to fix the out-of-bounds write warning Signed-off-by: Ma Jun Suggested-by: Christian König Reviewed-by: Tim Huang Signed-off-by: Alex Deucher

drm/amdgpu: fix overflowed array index read warning

2024-04-30T13:59:03Z

Clear overflowed array index read warning by cast operation. Signed-off-by: Tim Huang Reviewed-by: Alex Deucher Reviewed-by: Christian König Signed-off-by: Alex Deucher

drm/amdgpu: fix deadlock while reading mqd from debugfs

2024-03-27T13:30:34Z

An errant disk backup on my desktop got into debugfs and triggered the following deadlock scenario in the amdgpu debugfs files. The machine also hard-resets immediately after those lines are printed (although I wasn't able to reproduce that part when reading by hand): [ 1318.016074][ T1082] ====================================================== [ 1318.016607][ T1082] WARNING: possible circular locking dependency detected [ 1318.017107][ T1082] 6.8.0-rc7-00015-ge0c8221b72c0 #17 Not tainted [ 1318.017598][ T1082] ------------------------------------------------------ [ 1318.018096][ T1082] tar/1082 is trying to acquire lock: [ 1318.018585][ T1082] ffff98c44175d6a0 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x40/0x80 [ 1318.019084][ T1082] [ 1318.019084][ T1082] but task is already holding lock: [ 1318.020052][ T1082] ffff98c4c13f55f8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: amdgpu_debugfs_mqd_read+0x6a/0x250 [amdgpu] [ 1318.020607][ T1082] [ 1318.020607][ T1082] which lock already depends on the new lock. [ 1318.020607][ T1082] [ 1318.022081][ T1082] [ 1318.022081][ T1082] the existing dependency chain (in reverse order) is: [ 1318.023083][ T1082] [ 1318.023083][ T1082] -> #2 (reservation_ww_class_mutex){+.+.}-{3:3}: [ 1318.024114][ T1082] __ww_mutex_lock.constprop.0+0xe0/0x12f0 [ 1318.024639][ T1082] ww_mutex_lock+0x32/0x90 [ 1318.025161][ T1082] dma_resv_lockdep+0x18a/0x330 [ 1318.025683][ T1082] do_one_initcall+0x6a/0x350 [ 1318.026210][ T1082] kernel_init_freeable+0x1a3/0x310 [ 1318.026728][ T1082] kernel_init+0x15/0x1a0 [ 1318.027242][ T1082] ret_from_fork+0x2c/0x40 [ 1318.027759][ T1082] ret_from_fork_asm+0x11/0x20 [ 1318.028281][ T1082] [ 1318.028281][ T1082] -> #1 (reservation_ww_class_acquire){+.+.}-{0:0}: [ 1318.029297][ T1082] dma_resv_lockdep+0x16c/0x330 [ 1318.029790][ T1082] do_one_initcall+0x6a/0x350 [ 1318.030263][ T1082] kernel_init_freeable+0x1a3/0x310 [ 1318.030722][ T1082] kernel_init+0x15/0x1a0 [ 1318.031168][ T1082] ret_from_fork+0x2c/0x40 [ 1318.031598][ T1082] ret_from_fork_asm+0x11/0x20 [ 1318.032011][ T1082] [ 1318.032011][ T1082] -> #0 (&mm->mmap_lock){++++}-{3:3}: [ 1318.032778][ T1082] __lock_acquire+0x14bf/0x2680 [ 1318.033141][ T1082] lock_acquire+0xcd/0x2c0 [ 1318.033487][ T1082] __might_fault+0x58/0x80 [ 1318.033814][ T1082] amdgpu_debugfs_mqd_read+0x103/0x250 [amdgpu] [ 1318.034181][ T1082] full_proxy_read+0x55/0x80 [ 1318.034487][ T1082] vfs_read+0xa7/0x360 [ 1318.034788][ T1082] ksys_read+0x70/0xf0 [ 1318.035085][ T1082] do_syscall_64+0x94/0x180 [ 1318.035375][ T1082] entry_SYSCALL_64_after_hwframe+0x46/0x4e [ 1318.035664][ T1082] [ 1318.035664][ T1082] other info that might help us debug this: [ 1318.035664][ T1082] [ 1318.036487][ T1082] Chain exists of: [ 1318.036487][ T1082] &mm->mmap_lock --> reservation_ww_class_acquire --> reservation_ww_class_mutex [ 1318.036487][ T1082] [ 1318.037310][ T1082] Possible unsafe locking scenario: [ 1318.037310][ T1082] [ 1318.037838][ T1082] CPU0 CPU1 [ 1318.038101][ T1082] ---- ---- [ 1318.038350][ T1082] lock(reservation_ww_class_mutex); [ 1318.038590][ T1082] lock(reservation_ww_class_acquire); [ 1318.038839][ T1082] lock(reservation_ww_class_mutex); [ 1318.039083][ T1082] rlock(&mm->mmap_lock); [ 1318.039328][ T1082] [ 1318.039328][ T1082] *** DEADLOCK *** [ 1318.039328][ T1082] [ 1318.040029][ T1082] 1 lock held by tar/1082: [ 1318.040259][ T1082] #0: ffff98c4c13f55f8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: amdgpu_debugfs_mqd_read+0x6a/0x250 [amdgpu] [ 1318.040560][ T1082] [ 1318.040560][ T1082] stack backtrace: [ 1318.041053][ T1082] CPU: 22 PID: 1082 Comm: tar Not tainted 6.8.0-rc7-00015-ge0c8221b72c0 #17 3316c85d50e282c5643b075d1f01a4f6365e39c2 [ 1318.041329][ T1082] Hardware name: Gigabyte Technology Co., Ltd. B650 AORUS PRO AX/B650 AORUS PRO AX, BIOS F20 12/14/2023 [ 1318.041614][ T1082] Call Trace: [ 1318.041895][ T1082] [ 1318.042175][ T1082] dump_stack_lvl+0x4a/0x80 [ 1318.042460][ T1082] check_noncircular+0x145/0x160 [ 1318.042743][ T1082] __lock_acquire+0x14bf/0x2680 [ 1318.043022][ T1082] lock_acquire+0xcd/0x2c0 [ 1318.043301][ T1082] ? __might_fault+0x40/0x80 [ 1318.043580][ T1082] ? __might_fault+0x40/0x80 [ 1318.043856][ T1082] __might_fault+0x58/0x80 [ 1318.044131][ T1082] ? __might_fault+0x40/0x80 [ 1318.044408][ T1082] amdgpu_debugfs_mqd_read+0x103/0x250 [amdgpu 8fe2afaa910cbd7654c8cab23563a94d6caebaab] [ 1318.044749][ T1082] full_proxy_read+0x55/0x80 [ 1318.045042][ T1082] vfs_read+0xa7/0x360 [ 1318.045333][ T1082] ksys_read+0x70/0xf0 [ 1318.045623][ T1082] do_syscall_64+0x94/0x180 [ 1318.045913][ T1082] ? do_syscall_64+0xa0/0x180 [ 1318.046201][ T1082] ? lockdep_hardirqs_on+0x7d/0x100 [ 1318.046487][ T1082] ? do_syscall_64+0xa0/0x180 [ 1318.046773][ T1082] ? do_syscall_64+0xa0/0x180 [ 1318.047057][ T1082] ? do_syscall_64+0xa0/0x180 [ 1318.047337][ T1082] ? do_syscall_64+0xa0/0x180 [ 1318.047611][ T1082] entry_SYSCALL_64_after_hwframe+0x46/0x4e [ 1318.047887][ T1082] RIP: 0033:0x7f480b70a39d [ 1318.048162][ T1082] Code: 91 ba 0d 00 f7 d8 64 89 02 b8 ff ff ff ff eb b2 e8 18 a3 01 00 0f 1f 84 00 00 00 00 00 80 3d a9 3c 0e 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 53 48 83 [ 1318.048769][ T1082] RSP: 002b:00007ffde77f5c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 1318.049083][ T1082] RAX: ffffffffffffffda RBX: 0000000000000800 RCX: 00007f480b70a39d [ 1318.049392][ T1082] RDX: 0000000000000800 RSI: 000055c9f2120c00 RDI: 0000000000000008 [ 1318.049703][ T1082] RBP: 0000000000000800 R08: 000055c9f2120a94 R09: 0000000000000007 [ 1318.050011][ T1082] R10: 0000000000000000 R11: 0000000000000246 R12: 000055c9f2120c00 [ 1318.050324][ T1082] R13: 0000000000000008 R14: 0000000000000008 R15: 0000000000000800 [ 1318.050638][ T1082] amdgpu_debugfs_mqd_read() holds a reservation when it calls put_user(), which may fault and acquire the mmap_sem. This violates the established locking order. Bounce the mqd data through a kernel buffer to get put_user() out of the illegal section. Fixes: 445d85e3c1df ("drm/amdgpu: add debugfs interface for reading MQDs") Cc: stable@vger.kernel.org # v6.5+ Reviewed-by: Shashank Sharma Signed-off-by: Johannes Weiner Signed-off-by: Alex Deucher

drm/amdgpu: Fix the warning info in mode1 reset

2024-01-31T22:34:05Z

Fix the warning info below during mode1 reset. [ +0.000004] Call Trace: [ +0.000004] [ +0.000006] ? show_regs+0x6e/0x80 [ +0.000011] ? __flush_work.isra.0+0x2e8/0x390 [ +0.000005] ? __warn+0x91/0x150 [ +0.000009] ? __flush_work.isra.0+0x2e8/0x390 [ +0.000006] ? report_bug+0x19d/0x1b0 [ +0.000013] ? handle_bug+0x46/0x80 [ +0.000012] ? exc_invalid_op+0x1d/0x80 [ +0.000011] ? asm_exc_invalid_op+0x1f/0x30 [ +0.000014] ? __flush_work.isra.0+0x2e8/0x390 [ +0.000007] ? __flush_work.isra.0+0x208/0x390 [ +0.000007] ? _prb_read_valid+0x216/0x290 [ +0.000008] __cancel_work_timer+0x11d/0x1a0 [ +0.000007] ? try_to_grab_pending+0xe8/0x190 [ +0.000012] cancel_work_sync+0x14/0x20 [ +0.000008] amddrm_sched_stop+0x3c/0x1d0 [amd_sched] [ +0.000032] amdgpu_device_gpu_recover+0x29a/0xe90 [amdgpu] This warning info was printed after applying the patch "drm/sched: Convert drm scheduler to use a work queue rather than kthread". The root cause is that amdgpu driver tries to use the uninitialized work_struct in the struct drm_gpu_scheduler v2: - Rename the function to amdgpu_ring_sched_ready and move it to amdgpu_ring.c (Alex) v3: - Fix a few more checks based on Vitaly's patch (Alex) v4: - squash in fix noticed by Bert in https://gitlab.freedesktop.org/drm/amd/-/issues/3139 Fixes: 11b3b9f461c5 ("drm/sched: Check scheduler ready before calling timeout handling") Reviewed-by: Alex Deucher Signed-off-by: Vitaly Prosyak Signed-off-by: Ma Jun Signed-off-by: Alex Deucher